The present invention discloses a novel device for producing pressure pulses in drilling mud medium flowing through a drill string casing. More particularly, a balanced, double guided mud pulse valve is disclosed herein.
With known devices of this type, see, e.g., U.S. Pat. No. 3,958,217 or U.S. Pat. No. 4,901,290, the main valve body is supported by the carrying body at the main valve's rear end into the direction of mud flow so that the valve's body can move axially. The main valve body also includes a tube projection on its front end facing the flow. This projection has a diameter smaller than the diameter of a narrow passage in the casing and extends through the narrow passage against the direction of the mud flow. The projection also includes side slits which form inlet openings for an internal flow channel. The present invention discloses an especially simple low wear and reliable device of the aforementioned type.